I looked up in dictionaries and found that
grave. Why do Japanese people use the word
grave in their names?(e.g. 大塚 愛) Or does this character have other meanings when it's used in names?
塚 is actually a mound or small hill. 大塚 translates literally as big-mound. It so happens that some graves were built as mounds, and so 塚 also came to be used to mean grave, but I don't think it is very commonly used in that sense now. There are a few Jomon era 貝塚 (kaizuka) around Tokyo, where the Jomon people disposed of their empty shellfish shells in mounds.
There is a story about Taira no Masakado, a Heian Era figure who had his head cut off in a power struggle to become emperor. He was so angry at having his head cut off that it flew all the way from Kyoto to what is now Otemachi, Tokyo. There it remains (supposedly) under the "Taira no Masakado no kubizuka (平将門首塚)", a small mound with a memorial on top. According to local folk legend, MacArthur wanted to remove it, but the men who tried suffered a terrible fate, so it was left as it is. Rumor also has it jinxed MacArthur's chance of becoming president.